DESCRIPTION (provided by applicant): Stage theories of health behavior have been influential over the past 20 years. In the case of smoking cessation, the appeal and potential of a stage model is easily understood. Whereas many variables are associated with smoking cessation, it is difficult to organize these variables into a coherent theory of how people quit smoking. A stage model could help bring structure to these variables in a way that would inform interventions. If smokers could be arranged in an ordered set of stages, then interventions could be designed for each stage to foster progressive stage movements leading ultimately to cessation. The intuitive appeal of a stage model for smoking cessation is reflected by the widespread use of the stages of change over past 20 years. The stage of change construct is the linchpin of a larger model known as the Transtheoretical Model (TTM). However, several researchers recently have concluded that the TTM is insufficiently supported by empirical evidence. The hypothesis of the current application is that the stage of change construct systematically underestimates motivation to quit smoking, and that this systematic underestimation undermines research and interventions based on the TTM. An intervention study is proposed in which participants receive stage-matched interventions for smoking cessation. The three study conditions will use three different staging systems to determine the stage of each smoker. One staging system will be the stages of change. A second staging method will be an alterative developed by the PI. Past research has shown that these two systems produce significantly different stage distributions, and that the alternative algorithm classifies smokers as being significantly more motivated to quit compared to the stages of change algorithm. A third "system" is a control condition in which all smokers are treated as though they were highly motivated to quit. The hypothesis of the proposed study is that participants staged using the alternative staging system will evince greater rates of cessation and greater increases in motivation to quit smoking compared to participants staged with the stage of change algorithm, or participants assigned to the control condition. Given the prominence of the TTM in public health research and practice, this study could have far reaching implications for preventing cancer and other diseases by enhancing the effectiveness of smoking cessation interventions.